What mass of oxygen gas is required for combustion of a #12.0*g# mass of propane?
We need (i) a stoichiometric equation:
Is it balanced? It's your problem not mine.
And (ii) we need equivalent quantities of propane and dioxygen.
Clearly, there is insufficient oxygen for complete combustion: we would require
So what would occur? Well, this is a case of incomplete combustion. I could invoke a stoichiometric equation of the sort:
Which are both still deficient with respect to the oxidant. This question is NOT well-proposed; certainly it is unsuitable for an A-level student, and it would tax many first year university students.
You could assume COMPLETE combustion on the basis of the first equation, but the product mix would likely have